Aircraft proximity device

ABSTRACT

Gyro circuitry, variable oscillator circuitry, and carrier suppressor circuitry for transmitting a carrier frequency determinative of the direction of travel of an object and for suppressing transmission when its receiver is tuned to the same frequency. An air speed indicator ganged with a rheostat, a variable audio oscillator, and a modulator for transmitting an audio tone determinative of the speed of the object. A receiver, a scanner, and tuning circuitry for converting the audio signal received from a traveling object into a visual indication of the direction in which that object is traveling.

United States Patent Neff et al.

[451 Dec. 5, 1972 [54] AIRCRAFT PROXIMITY DEVICE [72] Inventors: Ray A.Netf, Marshall, 111.; Dan D.

Gowings, Terre Haute, Ind.

[73] Assignee: Visu-Phonics, Incorporated, Terre Haute, Ind.

[22] Filed: March 2, 1970 [2]] Appl. No.: 15,560

[5 7 ABSTRACT Gyro circuitry, variable oscillator circuitry, and carriersuppressor circuitry for transmitting a carrier frequency determinativeof the direction of travel of an object and for suppressing transmissionwhen its receiver is [52] US. Cll. ..343/1l2 CA,(?;4I;/l;20 tuned to thesame frequency An air Speed indicator e l nil-- s l 1 a e u 1 I e u u ee 4 n e s s e I n e u u e l a a I l 0 can V a modulator for transmittingan audio tone determinative of the speed of the object. A receiver, ascanner, [56] References cued and tuning circuitry for converting theaudio signal UNITED STATES PATENTS received from a traveling object intoa visual indication of the direction in which that object is traveling.2.568568 9/]951 Stansbury ..343/] 12 CA UX 2.498333 2/1950 Wallace..343/l 12 CA UX 4 Claims, 3 Drawing Figures cow/ass 0/2 area 44 42arr/1mm? PoWE/Z Mum/Mme 4110/0 AMPl/F/[R 050/14 70/? (VAR/ABLE) CARR/ER5111 25850,?

lo 0 I80 56 E m-I'm it RECEIVE/i /V RECE/l/ER TUNER AIRCRAFT PROXIMITYDEVICE This invention relates to a device which is carried by anaircraft, ship, vehicle, or any other type of traveling objects for thedetermining of the direction of travel and the speed of other objectswithin a certain range of the device.

Most collisions and near misses between aircraft occur in marginalweather where there are craft on both instrument flight regulations(IFR) and visual flight regulations (VFR) in the same area or whereforward observation is reduced. Very often one or both of the aircraftinvolved are traveling at speeds in excess of two hundred and fiftyknots with the assumption that they are the only aircraft in that airspace. This invention makes the pilot aware of other craft within a tomile range although he still is not sure where they are. However, oncethe craft are known to be within the vicinity, a direction finder orintercom may establish their location and the pilot may sight the othercraft visually. This simple, low cost, and light weight device has beeninvented to fill the gap between no electronic equipment on a craft andsophisticated, expensive and heavy equipment on a craft such as radarsystems in the hope of promoting widespread use of an electronicproximity device for all types of planes including commercial andprivate craft. It should be noted that this invention may also form theheart of a much more sophisticated proximity device whereby acomputerized system would keep trace of all craft in the area andproject their activities onto a screen or cathode ray tube.

Accordingly, a primary object of this invention is to provide a devicefor indicating the direction of travel and the speed of an object whichis carrying the device.

Another object of this invention is to provide a device for suppressingthe transmission of the direction of travel of an object when it wouldinterfere with the reception of the direction of travel and speed ofanother object in the vicinity.

Still another object of this invention is to provide a device forconverting an audio signal to a visual indication of heading of anotherobject.

A further object of this invention is to provide a device for receivinga signal indicative of the direction of travel in which an object ismoving.

The above and other objects of the invention will become apparent tothose skilled in the art after a consideration of the following detaildescription of the preferred embodiments of this invention takentogether with the accompanying drawings in which:

FIG. I is a block diagram of the proximity device;

FIG. 2 is a schematic of a heading (direction of travel) to frequencyconverter;

FIG. 3 is a schematic of the carrier suppressor.

Referring to the drawing in greater detail, there is shown in FIG. 1 aradio transmitter having a variable frequency oscillator 20. Oscillator20 provides a carrier signal having a frequency which is automaticallydetermined by a compass or a gyro 22. The signal is amplified by a poweramplifier 24 and transmitted by means of antenna 26.

FIG. 2 shows a directional device 28 such as compass or gyro 22 havingautomatic qualities for allowing constant adjustment of the frequency ofthe transmitter carrier for continuously reflecting the heading of thecraft on which the transmitter is installed. Directional device 28 has ashaft 30 for changing the capacitance of a variable condenser 32 of theL-C circuit 34 of variable frequency oscillator 20.

The carrier wave transmitted by antenna 26-is modulated with a wave, theform of which is indicative of the speed of the craft. In its simplestform the wave would be a sine wave with a frequency in the audible rangewith the lower speeds being represented by lower tones and the higherspeeds being represented by higher tones. The arm 36 of an air speedindicator 38 is ganged with a rheostat 40 for varying an audiooscillator 42 which is connected to a modulator 44.

This invention also has a receiver (not shown) which covers thefrequency range of the transmitter and which is equipped with a scanningdevice so that the frequency range is continuously scanned in asystematic manner. The receiver is connected to an L-C circuit 50 whichis in turn connected to a scanner drive motor 52 ganged with the arm 54of a scanner indicator S6. The scanner indicator 56 is set so that asthe receiver scans the frequencies, scanner indicator 56 will indicateto an observer the heading of other craft in the area when the receiverpicks up their signals and converts them to audible sound. The frequencyat which the signal is picked up would indicate the heading of the othercraft and would be read in degrees with 360being indicative of north.The beep signal picked up by the receiver will, when converted toaudible sound have a certain tone which is indicative of the speed ofthe craft from which the signal is coming. An example of the FCCfrequency allocation for transmission and reception of the carrierfrequency is shown below:

Heading Carrier Frequency North 360 150.000 MH East 150.250 MH South 180150.500 MH West 270 150.750 MH The following table is exemplary of thefrequencyspeed conversion that would be used in the system:

Speed Audio Frequency I00 MPH Cycles per second 200 MPH 600 CPS 300 MPH1500 CPS 400 MPH 2000 CPS 500 MPH 2500 CPS 600 MPH 3000 CPS etc.

Scanning Speeds 60 MPH l scan/minute 300 MPH 2 scans/minute 600 MPH 4scans/minute FIG. 3 shows scanner drive motor 52 connected to variablecondenser 60 in order to vary the capacitance of L-C circuit 50.Connected in series between L-C circuit 50 and power amplifier 24 is adetector 62 and a suppressor 64. As scanner indicator 56 tunes thereceiver on the craft to the frequency being transmitted by the craft,the carrier of the transmitter on the craft will be momentarilyinterrupted by suppressor 64 so that the craft does not receive its ownsignal and possibly fail to receive the signal of another craft on thesame heading. The circuit is so aligned that when the receiver is tunedto a certain frequency, L-C circuit 50 will be tuned to the samefrequency. When L-C circuit 50 is tuned to the frequency of thetransmitter, a voltage is induced into L-C circuit 50 and fed tosuppressor 64 which operates as a blocked-gridkeying circuit,momentarily removing the voltage from the final stage of power amplifier24 and thereby suppressing the carrier. Suppressor 64, it should benoted, could also be applied to oscillator 20 rather than amplifier 24in order to suppress the carrier.

When a plane takes off, the proximity device becomes active as soon asair speed indicator 38 advances enough to start scanner indicator 56 andraise the pitch of of the tone into the audible range. The unit willhave been tested before take-off and there would be clearance to makesure that it is operable. As the craft begins its climb out of theairport, the transmitter would be transmitting a carrier, the frequencyof which would be indicative of the heading of the aircraft, and thatcarrier would be modulated with a tone, the pitch of which would beindicative of its speed. This signal would be receivable by all craftand ground stations within a fifteen-twenty mile area. At the same time,the receiver would be scanning the frequency range of the system inorder to determine the presence of other aircraft in the samefifteen-twenty mile area.

While the preferred embodiments of this invention have been illustratedand described, it will be understood by those skilled in the art thatmodifications and changes may be resorted to without departing from thespirit and scope of the invention.

Iclaim:

1. A communications system, comprising:

first means including an antenna for transmitting a carrier frequencyindicative of the heading of a craft in which the communications systemis installed;

second means connected to said first means for modulating thetransmitter carrier frequency with an audio frequency indicative of thespeed of the craft;

third means connected to said second means for receiving and scanning amodulated carrier frequency from another craft and for converting thecarrier frequency received into a visual indication of the heading ofsaid other craft, said third means having a regulatable frequencyscanning speed, said second means regulating the frequency scanningspeed of said third means; and

fourth means connected between said first means and said third means forpreventing said third means for receiving the signal transmitted by saidfirst means.

2. The communications system of claim 1, wherein said second meanscomprises an air speed indicator ganged with a rheostat, a variableaudio oscillator controlled by said rheostat, a modulator, and a poweramplifier, said second means includinga second rheostat ganged with sa1first rheostat and sa1d air speed Indicator and connected to saidthirdmeans for regulating the scan frequency speed.

3. The communications system of claim 2, wherein said third meanscomprises a receiver having a variable tuning circuit, a variable L-Ccircuit, a motor, and a scanner indicator ganged together, said motoralso being connected to said second rheostat for regulating the speed ofthe motor.

4. The communications system of claim 3, wherein said fourth meanscomprises a detector and a suppressor in series between said poweramplifier and said L-C circuit for preventing transmission from saidantenna during the period of time said receiver is tuned to the carrierfrequency indicative of the direction of travel of the craft having saidantenna in order to receive the carrier frequency signal of said othercraft when said other craft is traveling in the same direction as thecraft having said antenna.

1. A communications system, comprising: first means including an antennafor transmitting a carrier frequency indicative of the heading of acraft in which the communications system is installed; second meansconnected to said first means for modulating the transmitter carrierfrequency with an audio frequency indicative of the speed of the craft;third means connected to said second means for receiving and scanning amodulated carrier frequency from another craft and for converting thecarrier frequency received into a visual indication of the heading ofsaid other craft, said third means having a regulatable frequencyscanning speed, said second means regulating the frequency scanningspeed of said third means; and fourth means connected between said firstmeans and said third means for preventing said third means for receivingthe signal transmitted by said first means.
 2. The communications systemof claim 1, wherein said second means comprises an air speed indicatorganged with a rheostat, a variable audio oscillator controlled by saidrheostat, a modulator, and a power amplifier, said second meansincluding a second rheostat ganged with said first rheostat and said airspeed indicator and connected to said third means for regulating thescan frequency speed.
 3. The communications system of claim 2, whereinsaid third means comprises a receiver having a variable tuning circuit,a variable L-C circuit, a motor, and a scanner indicator gangedtogether, said motor also being connected to said second rheostat forregulating the speed of the motor.
 4. The communications system of claim3, wherein said fourth means comprises a detector and a suppressor inseries between said power amplifier and said L-C circuit for preventingtransmission from said antenna during the period of time said receiveris tuned to the carrier frequency indicative of the direction of travelof the craft having said antenna in order to receive the carrierfrequency signal of said other craft when said other craft is travelingin the same direction as the craft having said antenna.